/* ezxml.c
 *
 * Copyright 2004-2006 Aaron Voisine <aaron@voisine.org>
 *
 * Permission is hereby granted, free of charge, to any person obtaining
 * a copy of this software and associated documentation files (the
 * "Software"), to deal in the Software without restriction, including
 * without limitation the rights to use, copy, modify, merge, publish,
 * distribute, sublicense, and/or sell copies of the Software, and to
 * permit persons to whom the Software is furnished to do so, subject to
 * the following conditions:
 *
 * The above copyright notice and this permission notice shall be included
 * in all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
 * IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
 * CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
 * TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
 * SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 */

#include <stdlib.h>
#include <stdio.h>
#include <stdarg.h>
#include <string.h>
#include <ctype.h>
#include <unistd.h>
#include <sys/types.h>
#ifndef EZXML_NOMMAP
#include <sys/mman.h>
#endif /* EZXML_NOMMAP */
#include <sys/stat.h>
#include "ezxml.h"

//#include "configure.h"
//#include "c_mem.h"

#define EZXML_WS   "\t\r\n "  /* whitespace */
#define EZXML_ERRL 128        /* maximum error string length */

typedef struct ezxml_root *ezxml_root_t;

struct ezxml_root /* additional data for the root tag */
{
  struct ezxml xml; 	/* is a super-struct built on top of ezxml struct */
  ezxml_t cur; 		/* current xml tree insertion point */
  char *m; 		/* original xml string */
  size_t len; 		/* length of allocated memory for mmap, -1 for malloc */
  char *u; 		/* UTF-8 conversion of string if original was UTF-16 */
  char *s; 		/* start of work area */
  char *e; 		/* end of work area */
  char **ent; 		/* general entities (ampersand sequences) */
  char ***attr; 	/* default attributes */
  char ***pi; 		/* processing instructions */
  short standalone; 	/* non-zero if <?xml standalone="yes"?> */
  char err[EZXML_ERRL]; /* error string */
};

char *EZXML_NIL[] = { NULL }; /* empty, null terminated array of strings */

/* returns the first child tag with the given name or NULL if not found */
ezxml_t ezxml_child(ezxml_t xml, const char *name)
{
  xml = (xml) ? xml->child : NULL;
  while (xml && strcmp(name, xml->name))
    xml = xml->sibling;

  return xml;
}

/* returns the first child tag with the given name or NULL if not found */
ezxml_t ezxml_case_child(ezxml_t xml, const char *name)
{
  xml = (xml) ? xml->child : NULL;
  while (xml && strcasecmp(name, xml->name))
    xml = xml->sibling;

  return xml;
}

/* returns the Nth tag with the same name in the same subsection
 *  or NULL if not found */
ezxml_t ezxml_idx(ezxml_t xml, int idx)
{
  for (; xml && idx; idx--)
    xml = xml->next;

  return xml;
}

/* returns the value of the requested tag attribute or NULL if not found */
const char *ezxml_attr(ezxml_t xml, const char *attr)
{
  int i = 0, j = 1;
  ezxml_root_t root = (ezxml_root_t) xml;

  if (!xml || !xml->attr)
    return NULL;

  while (xml->attr[i] && strcmp(attr, xml->attr[i]))
    i += 2;

  if (xml->attr[i])
    return xml->attr[i + 1]; /* found attribute */

  while (root->xml.parent)
    root = (ezxml_root_t) root->xml.parent; /* root tag */

  for (i = 0; root->attr[i] && strcmp(xml->name, root->attr[i][0]); i++)
    ;

  if (!root->attr[i])
    return NULL; /* no matching default attributes */

  while (root->attr[i][j] && strcmp(attr, root->attr[i][j]))
    j += 3;

  return (root->attr[i][j]) ? root->attr[i][j + 1] : NULL; /* found default */
}

/* same as ezxml_get but takes an already initialized va_list */
static ezxml_t ezxml_vget(ezxml_t xml, va_list ap)
{
  char *name = va_arg(ap, char *);
  int idx = -1;

  if (name && *name)
  {
    idx = va_arg(ap, int);
    xml = ezxml_child(xml, name);
  }

  return (idx < 0) ? xml : ezxml_vget(ezxml_idx(xml, idx), ap);
}

/* Traverses the xml tree to retrieve a specific subtag. Takes a variable
 * length list of tag names and indexes. The argument list must be terminated
 * by either an index of -1 or an empty string tag name. Example:
 * title = ezxml_get(library, "shelf", 0, "book", 2, "title", -1);
 * This retrieves the title of the 3rd book on the 1st shelf of library.
 * Returns NULL if not found. */
ezxml_t ezxml_get(ezxml_t xml, ...)
{
  va_list ap;
  ezxml_t r;

  va_start(ap, xml);
  r = ezxml_vget(xml, ap);
  va_end(ap);

  return r;
}

/* returns a null terminated array of processing instructions for the given
 * target */
const char **ezxml_pi(ezxml_t xml, const char *target)
{
  ezxml_root_t root = (ezxml_root_t) xml;
  int i = 0;

  if (!root)
    return (const char **) EZXML_NIL;

  while (root->xml.parent)
    root = (ezxml_root_t) root->xml.parent; /* root tag */

  while (root->pi[i] && strcmp(target, root->pi[i][0]))
    i++; /* find target */

  return (const char **) ((root->pi[i]) ? root->pi[i] + 1 : EZXML_NIL);
}

/* set an error string and return root */
static ezxml_t ezxml_err(ezxml_root_t root, char *s, const char *err, ...)
{
  va_list ap;
  int line = 1;
  char *t, fmt[EZXML_ERRL];

  for (t = root->s; t < s; t++)
  {
    if (*t == '\n')
      line++;
  }

  snprintf(fmt, EZXML_ERRL, "[error near line %d]: %s", line, err);

  va_start(ap, err);
  vsnprintf(root->err, EZXML_ERRL, fmt, ap);
  va_end(ap);

  return &root->xml;
}

/* Recursively decodes entity and character references and normalizes new lines
 * ent is a null terminated array of alternating entity names and values. set t
 * to '&' for general entity decoding, '%' for parameter entity decoding, 'c'
 * for cdata sections, ' ' for attribute normalization, or '*' for non-cdata
 * attribute normalization. Returns s, or if the decoded string is longer than
 * s, returns a malloced string that must be freed. */
static char *ezxml_decode(char *s, char **ent, char t)
{
  char *e, *r = s, *m = s;
  long b, c, d, l;

  /* normalize line endings */
  for (; *s; s++)
  {
    while (*s == '\r')
    {
      *(s++) = '\n';
      if (*s == '\n')
	memmove(s, (s + 1), strlen(s));
    }
  }

  for (s = r;;)
  {
    while (*s && *s != '&' && (*s != '%' || t != '%') && !isspace(*s))
      s++;

    if (!*s)
      break;
    else if (t != 'c' && !strncmp(s, "&#", 2)) /* character reference */
    {
      if (s[2] == 'x')
	c = strtol(s + 3, &e, 16); /* base 16 */
      else
	c = strtol(s + 2, &e, 10); /* base 10 */

      if (!c || *e != ';') /* not a character ref */
      {
	s++;
	continue;
      }

      if (c < 0x80) /* US-ASCII subset */
	*(s++) = c;
      else /* multi-byte UTF-8 sequence */
      {
	for (b = 0, d = c; d; d /= 2)
	  b++; /* number of bits in c */

	b = (b - 2) / 5; /* number of bytes in payload */
	*(s++) = (0xFF << (7 - b)) | (c >> (6 * b)); /* head */

	while (b)
	  *(s++) = 0x80 | ((c >> (6 * --b)) & 0x3F); /* payload */
      }

      memmove(s, strchr(s, ';') + 1, strlen(strchr(s, ';')));
    }
    else if ((*s=='&' && (t=='&'||t==' '||t=='*')) || (*s=='%'&&t=='%'))
    {
      /* entity reference */
      for (b = 0; ent[b] && strncmp(s + 1, ent[b], strlen(ent[b])); b += 2)
	; /* find entity in entity list */

      if (ent[b++]) /* found a match */
      {
	if ((c = strlen(ent[b])) - 1 > (e = strchr(s, ';')) - s)
	{
	  l = (d = (s - r)) + c + strlen(e); /* new length */
	  r = (r == m) ? strcpy(malloc(l), r) : realloc(r, l);
	  e = strchr((s = r + d), ';'); /* fix up pointers */
	}

	memmove(s + c, e + 1, strlen(e)); /* shift rest of string */
	strncpy(s, ent[b], c); /* copy in replacement text */
      }
      else
	s++; /* not a known entity */
    }
    else if ((t == ' ' || t == '*') && isspace(*s))
      *(s++) = ' ';
    else
      s++; /* no decoding needed */
  }

  if (t == '*') /* normalize spaces for non-cdata attributes */
  {
    for (s = r; *s; s++)
    {
      if ((l = strspn(s, " ")))
	memmove(s, s + l, strlen(s + l) + 1);

      while (*s && *s != ' ')
	s++;
    }

    if (--s >= r && *s == ' ')
      *s = '\0'; /* trim any trailing space */
  }

  return r;
}

/* called when parser finds start of new tag */
static void ezxml_open_tag(ezxml_root_t root, char *name, char **attr)
{
  ezxml_t xml = root->cur;

  if (xml->name)
    xml = ezxml_add_child(xml, name, strlen(xml->txt));
  else
    xml->name = name; /* first open tag */

  xml->attr = attr;
  root->cur = xml; /* update tag insertion point */
}

/* called when parser finds character content between open and closing tag */
static void ezxml_char_content(ezxml_root_t root, char *s, size_t len, char t)
{
  ezxml_t xml = root->cur;
  char *m = s;
  size_t l;

  if (!xml || !xml->name || !len)
    return; /* sanity check */

  s[len] = '\0'; /* null terminate text (calling functions anticipate this) */
  while(s[--len]=='\r' || s[len]=='\n')
    s[len] = '\0';

  len = strlen(s = ezxml_decode(s, root->ent, t)) + 1;

  if (!*(xml->txt)) /* initial character content */
    xml->txt = s;
  else /* allocate our own memory and make a copy */
  {
    xml->txt = (xml->flags & EZXML_TXTM) /* allocate some space */
		     ? realloc(xml->txt, (l=strlen(xml->txt))+len)
		     : strcpy(malloc((l=strlen(xml->txt))+ len), xml->txt);

    strcpy(xml->txt + l, s); /* add new char content */
    if (s != m)
      free(s); /* free s if it was malloced by ezxml_decode() */
  }

  if (xml->txt != m)
    ezxml_set_flag(xml, EZXML_TXTM);
}

/* called when parser finds closing tag */
static ezxml_t ezxml_close_tag(ezxml_root_t root, char *name, char *s)
{
  if (!root->cur || !root->cur->name || strcmp(name, root->cur->name))
    return ezxml_err(root, s, "unexpected closing tag </%s>", name);

  root->cur = root->cur->parent;
  return NULL;
}

/* checks for circular entity references, returns non-zero if no circular
 * references are found, zero otherwise */
static int ezxml_ent_ok(char *name, char *s, char **ent)
{
  int i;

  for (;; s++)
  {
    while (*s && *s != '&')
      s++; /* find next entity reference */

    if (!*s)
      return 1;

    if (!strncmp(s + 1, name, strlen(name)))
      return 0; /* circular ref. */

    for (i = 0; ent[i] && strncmp(ent[i], s + 1, strlen(ent[i])); i += 2)
      ;

    if (ent[i] && !ezxml_ent_ok(name, ent[i + 1], ent))
      return 0;
  }
}

/* called when the parser finds a processing instruction */
static void ezxml_proc_inst(ezxml_root_t root, char *s, size_t len)
{
  int i = 0, j = 1;
  char *target = s;

  s[len] = '\0'; /* null terminate instruction */
  if (*(s += strcspn(s, EZXML_WS)))
  {
    *s = '\0'; /* null terminate target */
    s += strspn(s + 1, EZXML_WS) + 1; /* skip whitespace after target */
  }

  if (!strcmp(target, "xml")) /* <?xml ... ?> */
  {
    if ((s = strstr(s, "standalone"))
	&& !strncmp(s+strspn(s+10, EZXML_WS "='\"")+10, "yes", 3))
      root->standalone = 1;

    return;
  }

  if (!root->pi[0])
    *(root->pi = malloc(sizeof(char **))) = NULL; /*first pi */

  while (root->pi[i] && strcmp(target, root->pi[i][0]))
    i++; /* find target */

  if (!root->pi[i]) /* new target */
  {
    root->pi = realloc(root->pi, sizeof(char **) * (i + 2));
    root->pi[i] = malloc(sizeof(char *) * 3);
    root->pi[i][0] = target;
    root->pi[i][1] = (char *) (root->pi[i + 1] = NULL); /* terminate pi list */
    root->pi[i][2] = strdup(""); /* empty document position list */
  }

  /* find end of instruction list for this target */
  while (root->pi[i][j])
    j++;

  root->pi[i] = realloc(root->pi[i], sizeof(char *) * (j + 3));
  root->pi[i][j + 2] = realloc(root->pi[i][j + 1], j + 1);
  strcpy(root->pi[i][j + 2] + j - 1, (root->xml.name) ? ">" : "<");
  root->pi[i][j + 1] = NULL; /* null terminate pi list for this target */
  root->pi[i][j] = s; /* set instruction */
}

/* called when the parser finds an internal doctype subset */
static short ezxml_internal_dtd(ezxml_root_t root, char *s, size_t len)
{
  char q, *c, *t, *n = NULL, *v, **ent, **pe;
  int i, j;

  pe = memcpy(malloc(sizeof(EZXML_NIL)), EZXML_NIL, sizeof(EZXML_NIL));

  for (s[len] = '\0'; s;)
  {
    while (*s && *s != '<' && *s != '%')
      s++; /* find next declaration */

    if (!*s)
      break;
    else if (!strncmp(s, "<!ENTITY", 8)) /* parse entity definitions */
    {
      c = s += strspn(s + 8, EZXML_WS) + 8; /* skip white space separator */
      n = s + strspn(s, EZXML_WS "%"); /* find name */
      *(s = n + strcspn(n, EZXML_WS)) = ';'; /* append ; to name */

      v = s + strspn(s + 1, EZXML_WS) + 1; /* find value */
      if ((q = *(v++)) != '"' && q != '\'') /* skip externals */
      {
	s = strchr(s, '>');
	continue;
      }

      for (i = 0, ent = (*c == '%') ? pe : root->ent; ent[i]; i++)
	;

      ent = realloc(ent, (i+3) * sizeof(char *)); /* space for next ent */
      if (*c == '%')
	pe = ent;
      else
	root->ent = ent;

      *(++s) = '\0'; /* null terminate name */
      if ((s = strchr(v, q)))
	*(s++) = '\0'; /* null terminate value */

      ent[i + 1] = ezxml_decode(v, pe, '%'); /* set value */
      ent[i + 2] = NULL; /* null terminate entity list */
      if (!ezxml_ent_ok(n, ent[i + 1], ent)) /* circular reference */
      {
	if (ent[i + 1] != v)
	  free(ent[i + 1]);

	ezxml_err(root, v, "circular entity declaration &%s", n);
	break;
      }
      else
	ent[i] = n; /* set entity name */
    }
    else if (!strncmp(s, "<!ATTLIST", 9)) /* parse default attributes */
    {
      t = s + strspn(s + 9, EZXML_WS) + 9; /* skip whitespace separator */
      if (!*t)
      {
	ezxml_err(root, t, "unclosed <!ATTLIST");
	break;
      }

      if (*(s = t + strcspn(t, EZXML_WS ">")) == '>')
	continue;
      else
	*s = '\0'; /* null terminate tag name */

      for (i = 0; root->attr[i] && strcmp(n, root->attr[i][0]); i++)
	;

      while (*(n = ++s + strspn(s, EZXML_WS)) && *n != '>')
      {
	if (*(s = n + strcspn(n, EZXML_WS)))
	  *s = '\0'; /* attr name */
	else
	{
	  ezxml_err(root, t, "malformed <!ATTLIST");
	  break;
	}

	s += strspn(s + 1, EZXML_WS) + 1; /* find next token */
	c = (strncmp(s, "CDATA", 5)) ? "*" : " "; /* is it cdata? */
	if (!strncmp(s, "NOTATION", 8))
	  s += strspn(s + 8, EZXML_WS) + 8;

	s = (*s == '(') ? strchr(s, ')') : s + strcspn(s, EZXML_WS);
	if (!s)
	{
	  ezxml_err(root, t, "malformed <!ATTLIST");
	  break;
	}

	s += strspn(s, EZXML_WS ")"); /* skip white space separator */
	if (!strncmp(s, "#FIXED", 6))
	  s += strspn(s + 6, EZXML_WS) + 6;

	if (*s == '#') /* no default value */
	{
	  s += strcspn(s, EZXML_WS ">") - 1;
	  if (*c == ' ')
	    continue; /* cdata is default, nothing to do */

	  v = NULL;
	}
	else if ((*s == '"' || *s == '\'') && /* default value */
	    (s = strchr(v = s + 1, *s)))
	  *s = '\0';
	else
	{
	  ezxml_err(root, t, "malformed <!ATTLIST");
	  break;
	}

	if (!root->attr[i]) /* new tag name */
	{
	  root->attr = (!i) ? malloc(2 * sizeof(char **))
			    : realloc(root->attr, (i+2) * sizeof(char **));

	  root->attr[i] = malloc(2 * sizeof(char *));
	  root->attr[i][0] = t; /* set tag name */
	  root->attr[i][1] = (char *) (root->attr[i + 1] = NULL);
	}

	for (j = 1; root->attr[i][j]; j += 3)
	  ; /* find end of list */

	root->attr[i] = realloc(root->attr[i], (j + 4) * sizeof(char *));

	root->attr[i][j + 3] = NULL; /* null terminate list */
	root->attr[i][j + 2] = c; /* is it cdata? */
	root->attr[i][j + 1] = (v) ? ezxml_decode(v, root->ent, *c) : NULL;
	root->attr[i][j] = n; /* attribute name */
      }
    }
    else if (!strncmp(s, "<!--", 4))
      s = strstr(s + 4, "-->"); /* comments */
    else if (!strncmp(s, "<?", 2)) /* processing instructions */
    {
      if ((s = strstr(c = s + 2, "?>")))
	ezxml_proc_inst(root, c, s++ - c);
    }
    else if (*s == '<')
      s = strchr(s, '>'); /* skip other declarations */
    else if (*(s++) == '%' && !root->standalone)
      break;
  }

  free(pe);
  return !*root->err;
}

/* Converts a UTF-16 string to UTF-8. Returns a new string that must be freed
 * or NULL if no conversion was needed. */
static char *ezxml_str2utf8(char **s, size_t *len)
{
  char *u;
  size_t l = 0, sl, max = *len;
  long c, d;
  int b, be = (**s == '\xFE') ? 1 : (**s == '\xFF') ? 0 : -1;

  if (be == -1)
    return NULL; /* not UTF-16 */

  u = malloc(max);
  for (sl = 2; sl < *len - 1; sl += 2)
  {
    c = (be) ? (((*s)[sl] & 0xFF) << 8) | ((*s)[sl + 1] & 0xFF) /*UTF-16BE */
	     : (((*s)[sl + 1] & 0xFF) << 8) | ((*s)[sl] & 0xFF); /*UTF-16LE */

    if (c >= 0xD800 && c <= 0xDFFF && (sl += 2) < *len - 1) /* high-half */
    {
      d = (be) ? (((*s)[sl] & 0xFF) << 8) | ((*s)[sl+1] & 0xFF)
               : (((*s)[sl+1] & 0xFF) << 8) | ((*s)[sl] & 0xFF);
      c = (((c & 0x3FF) << 10) | (d & 0x3FF)) + 0x10000;
    }

    while (l + 6 > max)
      u = realloc(u, max += EZXML_BUFSIZE);

    if (c < 0x80)
      u[l++] = c; /* US-ASCII subset */
    else /* multi-byte UTF-8 sequence */
    {
      for (b = 0, d = c; d; d /= 2)
	b++; /* bits in c */

      b = (b - 2) / 5; /* bytes in payload */
      u[l++] = (0xFF << (7 - b)) | (c >> (6 * b)); /* head */

      while (b)
	u[l++] = 0x80 | ((c >> (6 * --b)) & 0x3F); /* payload */
    }
  }
  return *s = realloc(u, *len = l);
}

/* frees a tag attribute list */
static void ezxml_free_attr(char **attr)
{
  int i = 0;
  char *m;

  if (!attr || attr == EZXML_NIL)
    return; /* nothing to free */

  while (attr[i])
    i += 2; /* find end of attribute list */

  m = attr[i + 1]; /* list of which names and values are malloced */
  for (i = 0; m[i]; i++)
  {
    if (m[i] & EZXML_NAMEM)
      free(attr[i * 2]);

    if (m[i] & EZXML_TXTM)
      free(attr[(i * 2) + 1]);
  }

  free(m);
  free(attr);
}

/* parse the given xml string and return an ezxml structure */
ezxml_t ezxml_parse_str(char *s, size_t len)
{
  ezxml_root_t root = (ezxml_root_t) ezxml_new(NULL);
  char q, e, *d, **attr, **a = NULL; /* initialize a to avoid compile warning */
  int l, i, j;

  root->m = s;
  if (!len)
    return ezxml_err(root, NULL, "root tag missing");

  root->u = ezxml_str2utf8(&s, &len); /* convert utf-16 to utf-8 */
  root->e = (root->s = s) + len; /* record start and end of work area */

  e = s[len - 1]; /* save end char */
  s[len - 1] = '\0'; /* turn end char into null terminator */

  /* skip header spaces */
  while (*s && isspace(*s))
    s++;

  /* top level must is a tag */
  if (*s && *s != '<')
    return ezxml_err(root, s, "invalid XML root tag, is it a XML document?");

  if (!(*s))
    return ezxml_err(root, s, "root tag missing");

  for (;;)
  {
    attr = (char **) EZXML_NIL;
    d = ++s;

    if (isalpha(*s) || *s == '_' || *s == ':' || *s < '\0') /* new tag */
    {
      if (!root->cur)
	return ezxml_err(root, d, "markup outside of root element");

      s += strcspn(s, EZXML_WS "/>");
      while (isspace(*s))
	*(s++) = '\0'; /* null terminate tag name */

      if (*s && *s != '/' && *s != '>') /* find tag in default attr list */
	for (i = 0; (a = root->attr[i]) && strcmp(a[0], d); i++)
	  ;

      for (l = 0; *s && *s != '/' && *s != '>'; l += 2) /* new attrib */
      {
	attr = (l) ? realloc(attr, (l+4)*sizeof(char *))
	           : malloc(4*sizeof(char *)); /* allocate space */

	attr[l + 3] = (l) ? realloc(attr[l + 1], (l / 2) + 2)
	                  : malloc(2); /* mem for list of maloced vals */

	strcpy(attr[l + 3] + (l / 2), " "); 	/* value is not malloced */
	attr[l + 2] = NULL; 			/* null terminate list */
	attr[l + 1] = ""; 			/* temporary attribute value */
	attr[l] = s; 				/* set attribute name */

	s += strcspn(s, EZXML_WS "=/>");
	if (*s == '=' || isspace(*s))
	{
	  *(s++) = '\0'; /* null terminate tag attribute name */
	  q = *(s += strspn(s, EZXML_WS "="));

	  if (q == '"' || q == '\'') /* attribute value */
	  {
	    attr[l + 1] = ++s;
	    while (*s && *s != q)
	      s++;

	    if (*s)
	      *(s++) = '\0'; /* null terminate attribute val */
	    else
	    {
	      ezxml_free_attr(attr);
	      return ezxml_err(root, d, "missing %c", q);
	    }

	    for (j = 1; a && a[j] && strcmp(a[j], attr[l]); j += 3)
	      ;

	    attr[l + 1] = ezxml_decode(attr[l + 1], root->ent,
				       (a && a[j]) ? *a[j + 2] : ' ');

	    if (attr[l + 1] < d || attr[l + 1] > s)
	      attr[l + 3][l / 2] = EZXML_TXTM; /* value malloced */
	  }
	}

	while (isspace(*s))
	  s++;
      }

      if (*s == '/') /* self closing tag */
      {
	*(s++) = '\0';
	if ((*s && *s != '>') || (!*s && e != '>'))
	{
	  if (l)
	    ezxml_free_attr(attr);
	  return ezxml_err(root, d, "missing >");
	}

	ezxml_open_tag(root, d, attr);
	ezxml_close_tag(root, d, s);
      }
      else if ((q = *s) == '>' || (!*s && e == '>')) /* open tag */
      {
	*s = '\0'; /* temporarily null terminate tag name */
	ezxml_open_tag(root, d, attr);
	*s = q;
      }
      else
      {
	if (l)
	  ezxml_free_attr(attr);

	return ezxml_err(root, d, "missing >");
      }
    }
    else if (*s == '/') /* close tag */
    {
      s += strcspn(d = s + 1, EZXML_WS ">") + 1;
      if (!(q = *s) && e != '>')
	return ezxml_err(root, d, "missing >");

      *s = '\0'; /* temporarily null terminate tag name */
      if (ezxml_close_tag(root, d, s))
	return &root->xml;

      if (isspace(*s = q))
	s += strspn(s, EZXML_WS);
    }
    else if (!strncmp(s, "!--", 3)) /* xml comment */
    {
      if (!(s=strstr(s+3, "--")) || (*(s+=2)!='>' && *s) || (!*s && e!='>'))
	return ezxml_err(root, d, "unclosed <!--");
    }
    else if (!strncmp(s, "![CDATA[", 8)) /* cdata */
    {
      if ((s = strstr(s, "]]>")))
	ezxml_char_content(root, d + 8, (s += 2) - d - 10, 'c');
      else
	return ezxml_err(root, d, "unclosed <![CDATA[");
    }
    else if (!strncmp(s, "!DOCTYPE", 8)) /* dtd */
    {
      for (l = 0; *s && ((!l && *s != '>') || (l && (*s != ']' || *(s
	  + strspn(s + 1, EZXML_WS) + 1) != '>'))); l = (*s == '[') ? 1 : l)
	s += strcspn(s + 1, "[]>") + 1;

      if (!*s && e != '>')
	return ezxml_err(root, d, "unclosed <!DOCTYPE");

      d = (l) ? strchr(d, '[') + 1 : d;
      if (l && !ezxml_internal_dtd(root, d, s++ - d))
	return &root->xml;
    }
    else if (*s == '?') /* <?...?> processing instructions */
    {
      do
      {
	s = strchr(s, '?');
      } while (s && *(++s) && *s != '>');

      if (!s || (!*s && e != '>'))
	return ezxml_err(root, d, "unclosed <?");
      else
	ezxml_proc_inst(root, d + 1, s - d - 2);
    }
    else
      return ezxml_err(root, d, "unexpected <");

    if (!s || !*s)
      break;

    *s++ = '\0';
    while(*s && isspace(*s)) s++;
    d = s;

    if (*s && *s != '<') /* tag character content */
    {
      while (*s && *s != '<')
	s++;

      if (*s)
	ezxml_char_content(root, d, s - d, '&');
      else
	break;
    }
    else if (!*s)
      break;
  }

  if (!root->cur)
    return &root->xml;
  else if (!root->cur->name)
    return ezxml_err(root, d, "root tag missing");
  else
    return ezxml_err(root, d, "unclosed tag <%s>", root->cur->name);
}

/* Wrapper for ezxml_parse_str() that accepts a file stream. Reads the entire
 * stream into memory and then parses it. For xml files, use ezxml_parse_file()
 * or ezxml_parse_fd() */
ezxml_t ezxml_parse_fp(FILE *fp)
{
  ezxml_root_t root;
  size_t l, len = 0;
  char *s;

  if (!(s = malloc(EZXML_BUFSIZE)))
    return NULL;

  do
  {
    len += (l = fread((s + len), 1, EZXML_BUFSIZE, fp));
    if (l == EZXML_BUFSIZE)
      s = realloc(s, len + EZXML_BUFSIZE);
  } while (s && l == EZXML_BUFSIZE);

  if (!s)
    return NULL;

  root = (ezxml_root_t) ezxml_parse_str(s, len);
  root->len = -1; /* so we know to free s in ezxml_free() */

  return &root->xml;
}

/* A wrapper for ezxml_parse_str() that accepts a file descriptor. First
 * attempts to mem map the file. Failing that, reads the file into memory.
 * Returns NULL on failure. */
ezxml_t ezxml_parse_fd(int fd)
{
  ezxml_root_t root;
  struct stat st;
  size_t l;
  void *m;

  if (fd < 0)
    return NULL;

  fstat(fd, &st);

#ifndef EZXML_NOMMAP
  l = (st.st_size+sysconf(_SC_PAGESIZE)-1) & ~(sysconf(_SC_PAGESIZE)-1);

  if ((m = mmap(NULL, l, PROT_READ | PROT_WRITE, MAP_PRIVATE, fd, 0))
      != MAP_FAILED)
  {
    madvise(m, l, MADV_SEQUENTIAL); /* optimize for sequential access */
    root = (ezxml_root_t) ezxml_parse_str(m, st.st_size);
    madvise(m, root->len = l, MADV_NORMAL); /* put it back to normal */
  }
  else /* mmap failed, read file into memory */
  {
#endif /* EZXML_NOMMAP */
    l = read(fd, m = malloc(st.st_size), st.st_size);
    root = (ezxml_root_t) ezxml_parse_str(m, l);
    root->len = -1; /* so we know to free s in ezxml_free() */
#ifndef EZXML_NOMMAP
  }
#endif /* EZXML_NOMMAP */

  return &root->xml;
}

/* a wrapper for ezxml_parse_fd that accepts a file name */
ezxml_t ezxml_parse_file(const char *file)
{
  int fd = open(file, O_RDONLY, 0);
  ezxml_t xml = ezxml_parse_fd(fd);

  if (fd >= 0)
    close(fd);
  return xml;
}

/* Encodes ampersand sequences appending the results to *dst, reallocating *dst
 * if length excedes max. a is non-zero for attribute encoding. Returns *dst */
static char *ezxml_ampencode(const char *s, size_t len, char **dst, size_t *dlen,
		      size_t *max, short a)
{
  const char *e;

  for (e = s + len; s != e; s++)
  {
    while (*dlen + 10 > *max)
      *dst = realloc(*dst, *max += EZXML_BUFSIZE);

    switch (*s)
    {
      case '\0':
	return *dst;
      case '&':
	*dlen += sprintf(*dst + *dlen, "&amp;");
	break;
      case '<':
	*dlen += sprintf(*dst + *dlen, "&lt;");
	break;
      case '>':
	*dlen += sprintf(*dst + *dlen, "&gt;");
	break;
      case '"':
	*dlen += sprintf(*dst + *dlen, (a) ? "&quot;" : "\"");
	break;
      case '\n':
	*dlen += sprintf(*dst + *dlen, (a) ? "&#xA;" : "\n");
	break;
      case '\t':
	*dlen += sprintf(*dst + *dlen, (a) ? "&#x9;" : "\t");
	break;
      case '\r':
	*dlen += sprintf(*dst + *dlen, "&#xD;");
	break;
      default:
	(*dst)[(*dlen)++] = *s;
    }
  }
  return *dst;
}

/* Recursively converts each tag to xml appending it to *s. Reallocates *s if
 * its length excedes max. start is the location of the previous tag in the
 * parent tag's character content. Returns *s. */
static char *ezxml_toxml_r(ezxml_t xml, char **s, size_t *len, size_t *max,
		    size_t start, char ***attr, short flag)
{
  int i, j;
  char *txt = (xml->parent) ? xml->parent->txt : "";
  size_t off = 0;
  char strtab[256];

  memset(strtab, ' ', 256);
  if (flag&XML_INDENT)
    strtab[2*(flag&0xFF)] = '\0';
  else
    strtab[0] = '\0';

  /* parent character content up to this tag */
  *s = ezxml_ampencode(txt + start, xml->off - start, s, len, max, 0);

  while (*len + strlen(xml->name) + 4 > *max) /* reallocate s */
    *s = realloc(*s, *max += EZXML_BUFSIZE);

  *len += sprintf(*s + *len, "%s<%s", strtab, xml->name); /* open tag */
  for (i = 0; xml->attr[i]; i += 2) /* tag attributes */
  {
    if (ezxml_attr(xml, xml->attr[i]) != xml->attr[i + 1])
      continue;

    while (*len + strlen(xml->attr[i]) + 7 > *max) /* reallocate s */
      *s = realloc(*s, *max += EZXML_BUFSIZE);

    *len += sprintf(*s + *len, " %s=\"", xml->attr[i]);
    ezxml_ampencode(xml->attr[i + 1], -1, s, len, max, 1);
    *len += sprintf(*s + *len, "\"");
  }

  for (i = 0; attr[i] && strcmp(attr[i][0], xml->name); i++)
    ;

  for (j = 1; attr[i] && attr[i][j]; j += 3) /* default attributes */
  {
    if (!attr[i][j + 1] || ezxml_attr(xml, attr[i][j]) != attr[i][j + 1])
      continue; /* skip duplicates and non-values */

    while (*len + strlen(attr[i][j]) + 7 > *max) /* reallocate s */
      *s = realloc(*s, *max += EZXML_BUFSIZE);

    *len += sprintf(*s + *len, " %s=\"", attr[i][j]);
    ezxml_ampencode(attr[i][j + 1], -1, s, len, max, 1);
    *len += sprintf(*s + *len, "\"");
  }

  if (xml->child)
  {
    *len += sprintf(*s + *len, ">");
    if ((flag&XML_NEWLINE))
      *len += sprintf(*s + *len, "\n");
  }
  else
    *len += sprintf(*s + *len, (xml->txt && *xml->txt) ? ">" : " />");

  if (xml->child) /*child */
    *s = ezxml_toxml_r(xml->child, s, len, max, 0, attr, flag+1);
  else /*data */
   *s = ezxml_ampencode(xml->txt, -1, s, len, max, 0);

  while (*len + strlen(xml->name) + 4 > *max) /* reallocate s */
    *s = realloc(*s, *max += EZXML_BUFSIZE);

  /* close tag */
  if (xml->child)
  {
    if ((flag&XML_NEWLINE))
      *len += sprintf(*s + *len, "\n");
    *len += sprintf(*s + *len, "%s</%s>", strtab, xml->name);
  }
  else if (xml->txt && *xml->txt)
    *len += sprintf(*s + *len, "</%s>", xml->name);

  while (txt[off] && off < xml->off)
    off++; /* make sure off is within bounds */

  if ((flag&XML_NEWLINE) && xml->ordered)
    *len += sprintf(*s + *len, "\n");

  if (xml->ordered)
    return ezxml_toxml_r(xml->ordered, s, len, max, off, attr, flag);
  else
    return ezxml_ampencode(txt + off, -1, s, len, max, 0);
}

/* Converts an ezxml structure back to xml. Returns a string of xml data that
 * must be freed. */
char *ezxml_toxml(ezxml_t xml, short flag)
{
  ezxml_t p = (xml) ? xml->parent : NULL, o = (xml) ? xml->ordered : NULL;
  ezxml_root_t root = (ezxml_root_t) xml;
  size_t len = 0, max = EZXML_BUFSIZE;
  char *s = strcpy(malloc(max), ""), *t, *n;
  int i, j, k;

  if (!xml || !xml->name)
    return realloc(s, len + 1);

  while (root->xml.parent)
    root = (ezxml_root_t) root->xml.parent; /* root tag */

  /* pre-root processing instructions */
  for (i = 0; !p && root->pi[i]; i++)
  {
    for (k = 2; root->pi[i][k - 1]; k++)
      ;

    for (j = 1; (n = root->pi[i][j]); j++)
    {
      if (root->pi[i][k][j - 1] == '>')
	continue; /* not pre-root */

      while (len + strlen(t = root->pi[i][0]) + strlen(n) + 7 > max)
	s = realloc(s, max += EZXML_BUFSIZE);

      len += sprintf(s + len, "<?%s%s%s?>\n", t, *n ? " " : "", n);
    }
  }

  xml->parent = xml->ordered = NULL;
  s = ezxml_toxml_r(xml, &s, &len, &max, 0, root->attr, flag);
  xml->parent = p;
  xml->ordered = o;

  for (i = 0; !p && root->pi[i]; i++) /* post-root processing instructions */
  {
    for (k = 2; root->pi[i][k - 1]; k++)
      ;

    for (j = 1; (n = root->pi[i][j]); j++)
    {
      if (root->pi[i][k][j - 1] == '<')
	continue; /* not post-root */

      while (len + strlen(t = root->pi[i][0]) + strlen(n) + 7 > max)
	s = realloc(s, max += EZXML_BUFSIZE);

      len += sprintf(s + len, "\n<?%s%s%s?>", t, *n ? " " : "", n);
    }
  }
  return realloc(s, len + 1);
}

/* free the memory allocated for the ezxml structure */
void ezxml_free(ezxml_t xml)
{
  ezxml_root_t root = (ezxml_root_t) xml;
  int i, j;
  char **a, *s;

  if (!xml)
    return;

  ezxml_free(xml->child);
  ezxml_free(xml->ordered);

  if (!xml->parent) /* free root tag allocations */
  {
    for (i = 10; root->ent[i]; i += 2) /* 0 - 9 are default entites (<>&"') */
    {
      if ((s = root->ent[i + 1]) < root->s || s > root->e)
	free(s);
    }

    free(root->ent); /* free list of general entities */

    for (i = 0; (a = root->attr[i]); i++)
    {
      for (j = 1; a[j++]; j += 2) /* free malloced attribute values */
      {
	if (a[j] && (a[j] < root->s || a[j] > root->e))
	  free(a[j]);
      }

      free(a);
    }

    if (root->attr[0])
      free(root->attr); /* free default attribute list */

    for (i = 0; root->pi[i]; i++)
    {
      for (j = 1; root->pi[i][j]; j++)
	;

      free(root->pi[i][j + 1]);
      free(root->pi[i]);
    }

    if (root->pi[0])
      free(root->pi); /* free processing instructions */

    if (root->len == -1)
      free(root->m); /* malloced xml data */
#ifndef EZXML_NOMMAP
    else if (root->len)
      munmap(root->m, root->len); /* mem mapped xml data */
#endif /* EZXML_NOMMAP */

    if (root->u)
      free(root->u); /* utf8 conversion */
  }

  ezxml_free_attr(xml->attr); /* tag attributes */
  if ((xml->flags & EZXML_TXTM))
    free(xml->txt); /* character content */

  if ((xml->flags & EZXML_NAMEM))
    free(xml->name); /* tag name */

  free(xml);
}

/* return parser error message or empty string if none */
const char *ezxml_error(ezxml_t xml)
{
  while (xml && xml->parent)
    xml = xml->parent; /* find root tag */

  return (xml) ? ((ezxml_root_t) xml)->err : "";
}

/* returns a new empty ezxml structure with the given root tag name */
ezxml_t ezxml_new(const char *name)
{
  static char *ent[] =
  { "lt;", "&#60;", "gt;", "&#62;", "quot;", "&#34;", "apos;", "&#39;", "amp;",
    "&#38;", NULL };

  ezxml_root_t root = (ezxml_root_t)malloc(sizeof(struct ezxml_root));
  memset(root, '\0', sizeof(struct ezxml_root));

  root->xml.name = (char *) name;
  root->cur = &root->xml;
  strcpy(root->err, root->xml.txt = "");

  root->ent = memcpy(malloc(sizeof(ent)), ent, sizeof(ent));
  root->attr = root->pi = (char ***) (root->xml.attr = EZXML_NIL);

  return &root->xml;
}

/* inserts an existing tag into an ezxml structure */
ezxml_t ezxml_insert(ezxml_t xml, ezxml_t dest, size_t off)
{
  ezxml_t cur, prev, head;

  xml->next = xml->sibling = xml->ordered = NULL;
  xml->off = off;
  xml->parent = dest;

  if ((head = dest->child)) 	/* already have sub tags */
  {
    if (head->off <= off) 	/* not first subtag */
    {
      for (cur = head; cur->ordered && cur->ordered->off <= off; cur
	  = cur->ordered)
	;

      xml->ordered = cur->ordered;
      cur->ordered = xml;
    }
    else /* first subtag */
    {
      xml->ordered = head;
      dest->child = xml;
    }

    for (cur = head, prev = NULL; cur && strcmp(cur->name, xml->name);
	  prev=cur, cur=cur->sibling); /* find tag type */

    if (cur && cur->off <= off) /* not first of type */
    {
      while (cur->next && cur->next->off <= off)
	cur = cur->next;

      xml->next = cur->next;
      cur->next = xml;
    }
    else /* first tag of this type */
    {
      if (prev && cur)
	prev->sibling = cur->sibling; /* remove old first */

      xml->next = cur; /* old first tag is now next */

      for (cur=head, prev=NULL; cur && cur->off<=off; prev=cur, cur=cur->sibling)
	; /* new sibling insert point */

      xml->sibling = cur;
      if (prev)
	prev->sibling = xml;
    }
  }
  else
    dest->child = xml; /* only sub tag */

  return xml;
}

/* Adds a child tag. off is the offset of the child tag relative to the start
 * of the parent tag's character content. Returns the child tag. */
ezxml_t ezxml_add_child(ezxml_t xml, const char *name, size_t off)
{
  ezxml_t child;

  if (!xml)
    return NULL;
  child = (ezxml_t) memset(malloc(sizeof(struct ezxml)), '\0', sizeof(struct ezxml));
  child->name = (char *) name;
  child->attr = EZXML_NIL;
  child->txt = "";

  return ezxml_insert(child, xml, off);
}

/* sets the character content for the given tag and returns the tag */
ezxml_t ezxml_set_txt(ezxml_t xml, const char *txt)
{
  if (!xml)
    return NULL;

  if (xml->flags & EZXML_TXTM)
    free(xml->txt); /* existing txt was malloced */

  xml->flags &= ~EZXML_TXTM;
  xml->txt = (char *) txt;

  return xml;
}

/* Sets the given tag attribute or adds a new attribute if not found. A value
 * of NULL will remove the specified attribute. Returns the tag given. */
ezxml_t ezxml_set_attr(ezxml_t xml, const char *name, const char *value)
{
  int i = 0, c;

  if (!xml)
    return NULL;

  while (xml->attr[i] && strcmp(xml->attr[i], name))
    i += 2;

  if (!xml->attr[i]) /* not found, add as new attribute */
  {
    if (!value)
      return xml; /* nothing to do */

    if (xml->attr == EZXML_NIL) /* first attribute */
    {
      xml->attr = malloc(4 * sizeof(char *));
      xml->attr[1] = strdup(""); /* empty list of malloced names/vals */
    }
    else
      xml->attr = realloc(xml->attr, (i + 4) * sizeof(char *));

    xml->attr[i] = (char *) name; 	/* set attribute name */
    xml->attr[i + 2] = NULL; 		/* null terminate attribute list */
    xml->attr[i + 3] = realloc(xml->attr[i+1], (c=strlen(xml->attr[i+1]))+2);

    strcpy(xml->attr[i + 3] + c, " "); /* set name/value as not malloced */
    if (xml->flags & EZXML_DUP)
      xml->attr[i + 3][c] = EZXML_NAMEM;
  }
  else if (xml->flags & EZXML_DUP)
    free((char *) name); /* name was strduped */

  for (c = i; xml->attr[c]; c += 2)
    ; /* find end of attribute list */

  if (xml->attr[c + 1][i / 2] & EZXML_TXTM)
    free(xml->attr[i + 1]); /*old val */

  if (xml->flags & EZXML_DUP)
    xml->attr[c + 1][i / 2] |= EZXML_TXTM;
  else
    xml->attr[c + 1][i / 2] &= ~EZXML_TXTM;

  if (value)
    xml->attr[i + 1] = (char *) value; /* set attribute value */
  else /* remove attribute */
  {
    if (xml->attr[c + 1][i / 2] & EZXML_NAMEM)
      free(xml->attr[i]);

    memmove(xml->attr + i, xml->attr + i + 2, (c-i+2) * sizeof(char*));
    xml->attr = realloc(xml->attr, (c+2) * sizeof(char *));

    /* fix list of which name/vals are malloced */
    memmove(xml->attr[c+1]+(i/2), xml->attr[c+1]+(i/2)+1, (c/2)-(i/2));
  }

  xml->flags &= ~EZXML_DUP; /* clear strdup() flag */
  return xml;
}

/* sets a flag for the given tag and returns the tag */
ezxml_t ezxml_set_flag(ezxml_t xml, short flag)
{
  if (xml)
    xml->flags |= flag;

  return xml;
}

/* removes a tag along with its subtags without freeing its memory */
ezxml_t ezxml_cut(ezxml_t xml)
{
  ezxml_t cur;

  if (!xml)
    return NULL; /* nothing to do */

  if (xml->next)
    xml->next->sibling = xml->sibling; /* patch sibling list */

  if (xml->parent) /* not root tag */
  {
    cur = xml->parent->child; /* find head of subtag list */

    if (cur == xml)
      xml->parent->child = xml->ordered; /* first subtag */
    else /* not first subtag */
    {
      while (cur->ordered != xml)
	cur = cur->ordered;

      cur->ordered = cur->ordered->ordered; /* patch ordered list */

      cur = xml->parent->child; /* go back to head of subtag list */
      if (strcmp(cur->name, xml->name)) /* not in first sibling list */
      {
	while (strcmp(cur->sibling->name, xml->name))
	  cur = cur->sibling;

	if (cur->sibling == xml) /* first of a sibling list */
	  cur->sibling = (xml->next) ? xml->next : cur->sibling->sibling;
	else
	  cur = cur->sibling; /* not first of a sibling list */
      }

      while (cur->next && cur->next != xml)
	cur = cur->next;

      if (cur->next)
	cur->next = cur->next->next; /* patch next list */
    }
  }

  xml->ordered = xml->sibling = xml->next = NULL;

  return xml;
}

#ifdef EZXML_TEST /* test harness */
int main(int argc, char **argv)
{
  ezxml_t xml;
  char *s;
  int i=0;

  if (argc != 2)
    return fprintf(stderr, "usage: %s xmlfile\n", argv[0]);

  xml = ezxml_parse_file(argv[1]);

  printf("%s\n", (s = ezxml_toxml(xml, XML_NEWLINE|XML_INDENT)));
  free(s);

  i = fprintf(stderr, "%s\n", ezxml_error(xml));

  ezxml_free(xml);

  return (i) ? 1 : 0;
}
#endif /* EZXML_TEST */

